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Marcus Bleicher, Wrozlaw 2013 Hybrid Modeling of Heavy Ion Collisions Marcus Bleicher Frankfurt Institute for Advanced Studies Institut fr Theoretische Physik Goethe Universitt Frankfurt Germany

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How I learned that there is a right and wrong way to do thermodynamics ;-) Marcus Bleicher, Wrozlaw 2013 MB, KR, FB et al, Phys.Rev.Lett. 88 (2002) 202501

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Marcus Bleicher, Wrozlaw 2013 Thanks to Hannah Petersen (Hybrid model) now at FIAS Jan Steinheimer (Hybrid / EoS) now at LBL Marlene Nahrgang (Chiral Hydro) now at Duke Bjoern Baeuchle (Photons) Jochen Gerhard (GPU code) Yurii Karpenko (development of viscous hydro w/Nantes group) Pasi Huovinen (Hydro freeze-out) Hendrik van Hees (Heavy quark Langevin)

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Outline Introduction/Model Bulk: Photons Hard probes: Charm Potential improvements Summary Marcus Bleicher, Wrozlaw 2013

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Its not a uniform system... Marcus Bleicher, Wrozlaw 2013

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The need for dynamic simulations Initial State Pre-quilibrium QGP and hydro- dynamic expansion Hadronisation Hadronic phase and freeze-out Lattice gauge- theorie (lQCD): ab initio calculation of QCD quantities usually in thermodynamic limit Experiments: Observes the final state and penetrating probes Relies on theoretical predictions for the interpretation of the data Transport models & phenomenology: Provides explicit time and space dependence Direct view into the hot and dense matter Connects between fundamental calculations and observation

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Marcus Bleicher, Wrozlaw 2013 Present Hybrid Approaches Integrated (open source) UrQMD 3.3 H. Petersen, J. Steinheimer, M. Bleicher, Phys. Rev. C 78:044901, 2008 MUSIC@RHIC and LHC B. Schenke, S. Jeon, C. Gale,... (2008) Hadronic dissipative effects on elliptic flow in ultrarelativistic heavy-ion collisions. T. Hirano, U. Heinz, D. Kharzeev, R. Lacey, Y. Nara, Phys.Lett.B636:299- 304,2006 3-D hydro + cascade model at RHIC. C. Nonaka, S.A. Bass, Nucl.Phys.A774:873-876,2006 Results On Transverse Mass Spectra Obtained With Nexspherio F. Grassi, T. Kodama, Y. Hama, J.Phys.G31:S1041-S1044,2005 EPOS+Hydro+UrQMD at LHC K. Werner, M. Bleicher, T. Pierog, Phys. Rev. C (2010) Started with S. Bass, A. Dumitru, M. Bleicher, Phys.Rev.C60:021902,1999

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Marcus Bleicher, Wrozlaw 2013 Hybrid Approach Essential to draw conclusions from final state particle distributions about initially created medium (Petersen et al., PRC 78:044901, 2008, arXiv: 0806.1695) 1x 10 -23 s 10 x 10 -23 s30 x 10 -23 s Initial nuclei Quark Gluon Plasma/Hadronizatio n Detector Hadronic Non- equilibrium initial state Relativistic hydrodynamics Boltzmann

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Marcus Bleicher, Wrozlaw 2013 Initial State Contracted nuclei have passed through each other (at least 0.5 fm) Energy is deposited Baryon currents have separated Energy-, momentum- and baryon number densities are mapped onto the hydro grid Event-by-event fluctuations are taken into account Spectators are propagated separately in the cascade (J.Steinheimer et al., PRC 77,034901,2008) (nucl-th/0607018, nucl-th/0511021) E lab =40 AGeV b=0 fm

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Marcus Bleicher, Wrozlaw 2013 From H. Petersen

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Constraining Granularity Marcus Bleicher, Wrozlaw 2013 From H. Petersen

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Marcus Bleicher, Wrozlaw 2013 Equations of State Ideal relativistic one fluid dynamics: and HG: Hadron gas including the same degrees of freedom as in UrQMD (all hadrons with masses up to 2.2 GeV) CH: Chiral EoS from quark-meson model with first order transition and critical endpoint BM: Bag Model EoS with a strong first order phase transition between QGP and hadronic phase D. Rischke et al., NPA 595, 346, 1995, D. Zschiesche et al., PLB 547, 7, 2002 Papazoglou et al., PRC 59, 411, 1999 J. Steinheimer, et al., J. Phys. G38 (2011) 035001

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Phase diagram for the chiral EoS QGP fraction lambda Chiral PT Deconfinement PT CEP Parameters fixed to lQCD at mu=0 Full line: Deconfinement Dashed line: Chiral PT Marcus Bleicher, Wrozlaw 2013 J. Steinheimer, S. Schramm, H. Stoecker, J. Phys. G38 (2011) 035001

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Hadronization and Cooper-Frye Experiments observe finite number of hadrons in detectors Hadronization controlled by the equation of state Sampling of particles according to Cooper-Frye should: - Respect conservation laws, maybe even locally? -Introduces fluctuations on its own Sophisticated 3D hypersurface finder to resolve interesting structures in event-by-event simulations Petersen, Huovinen, arXiv:1206.3371 Marcus Bleicher, Wrozlaw 2013

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Final State Interactions (after Hydro)

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Hybrid models work up to LHC energies PbPb, 2.76 TeV Excellent description of centrality dependence, Transverse momenta, Elliptic flow. Marcus Bleicher, Wrozlaw 2013 H. Petersen, Phys.Rev. C84 (2011) 034912 chiral vs HG-EoS

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Marcus Bleicher, Wrozlaw 2013 Photon rates: hadronic and partonic Hadronic rate parametrization: QGP rate: Insert all rates into the hybrid model and compare to data. S. Turbide, R. Rapp, C. Gale, Phys. Rev. C69 (2004) 014903 P. Arnold, G. Moore, L. Yaffe, JHEP 0112 (2001)009

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Marcus Bleicher, Wrozlaw 2013 Comparison to data Bjoern Bauechle, MB, PRC (2010) Hybrid, QGP: ChannelsComparisons

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Heavy quarks at LHC Employ Rapp, van Hees-Langevin for heavy quarks in the dynamical background good description of data Marcus Bleicher, Wrozlaw 2013 T. Lang, H. van Hees, M. Bleicher, arxiv: 1208.1643

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Heavy quarks at RHIC Employ Rapp, van Hees-Langevin for heavy quarks in the dynamical background good description of data Marcus Bleicher, Wrozlaw 2013 T. Lang, H. van Hees, M. Bleicher, arxiv: 1208.1643

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improvements Marcus Bleicher, Wrozlaw 2013

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3+1d Simulation is working 100 Timesteps in FORTRAN ~60 min. 100 Timesteps in C++ Version ~15 min. J. Gerhard, M. Bleicher, V. Lindenstruth, arXiv:1206.0919, CPC2012 Marcus Bleicher, Wrozlaw 2013 * 100 Timesteps in OpenCL Version ~30 sec. * Factor 160 speed-up! (new cards: factor 400 !) Speeding things up: GPGPUs

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Aim: Explore signals for QCD first order phase transition and critical end point Model: Ideal quark fluid coupled to Polyakov-quark-meson model Propagate chiral fields and Polyakov loop explicitly via Langevin equations of motion Energy-momentum exchange between fields and fluid described by source terms M.Nahrgang, S.Leupold, C.Herold, M.Bleicher, PRC 84 (2011); M.Nahrgang, S.Leupold, M.Bleicher, PLB 711 (2012); M.Nahrgang, C.Herold, S.Leupold, M.Bleicher, I.Mishustin arXiv:1105.1962 Nonequilibrium Chiral Fluid Dynamics (N FD, PN FD) Solve with 3+1 dim. hydro, using SHASTA and staggered leap frog for the fields Marcus Bleicher, Wrozlaw 2013 (see also talk by H. van Hees and similar approach be C. Wesp)

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Fluctuations and quark densities C. Herold, M. Nahrgang, M. Bleicher, I. Mishustin Angular distribution, 12 fm/c 6 fm/c12 fm/c Crossover CP 1st o. PT Strong fluctuations,inhomogeneous quark densities Marcus Bleicher, Wrozlaw 2013

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Summary Hybrid models provide an excellent description of many data up to LHC - Bulk (Pions, Kaons, Protons), p_T, dN/dy - Hard probes (Charm, Bottom) - Photons, Dileptons Open questions remain: local coupling of currents, Cooper-Frye vs collision rates... Latest improvements: Classical field dynamics Marcus Bleicher, Wrozlaw 2013